Turn on your computer and simulate the future!

“The imaginative novelist is entitled to remake the existing world or present possible future worlds.” Thus Anthony Burgess, in his illuminating Encyclopaedia Britannica entry on “the novel,” claimed the right of his fellow novelists to transcend the real and present world. He could have claimed the same for scientists who simulate Earth’s climate.

Just as novelists plot the future consequences of current technologies such as nanoscience or genetic engineering, climate scientists investigate the future consequences of current conditions and policies.

But what future do you pick to imagine or simulate? The universe of possible future worlds is limitlessly diverse. Greg Egan set his 2002 novel Schild’s Ladder 20 000 years in Earth’s future and charted the repercussions of a universe-engulfing quantum experiment gone wrong.

Even though their simulations must obey the laws of nature, climate scientists are free to tackle a host of future conditions, likely or unlikely. In a 2004 paper, for example, David Keith and his collaborators simulated the effect on Earth’s climate of using wind-powered turbines to supply—somewhat fancifully—all of humanity’s energy needs.

Faced with unlimited choice, writers and scientists alike follow their fancies, interests, and politics. In his most famous book, A Clockwork Orange, Burgess examined a near-future Britain plagued by violent youth gangs kept in check by repressive countermeasures. He wrote it to come to terms with and understand his own brutal mugging. George Orwell depicted a similarly brutal near-future Britain in Nineteen Eighty-Four, but he intended his book to serve more as a general warning than a personal catharsis.

Different motivations can also engender similar work in climate science. The research staff at Swiss Re, one of the world’s largest insurance companies, simulates the effects of climate change to forestall financial losses and anticipate profits. But Swiss Re’s projections of the effects of climate change could have been produced by the greenest of university scientists.

And that’s the thing about personal motivation. You needn’t disclose it in your book, paper, or grant application. It’s there, of course, but only implicitly. So when a government official declares that scientists should stick to science, stay out of policy, and not talk to the press, you’re still free to turn on your computer and simulate whatever future you want—or dread.

This essay by Charles Day first appeared on page 88 of the May/June 2006 issue of Computing in Science & Engineering , a bimonthly magazine published jointly by the American Institute of Physics and IEEE Computer Society.